<!DOCTYPE html>
<html>
  <head>
    <style>
      #rel {
        position: relative;
        margin: 2px;
        padding: 0;
      }
      .abs {
        position: absolute;
        margin: 0;
        padding: 0;
        top: 25px;
        left: 25px;
        width: 50px;
        height: 50px;
        background-color: green;
      }
      #bad {
        background-color: blue;
      }
    </style>
  </head>
  <body>
    The green square should not completely cover the blue square.
    <div class="abs" id="bad"></div>
    <div id="rel">
      <div class="abs"></div>
    </div>
  </body>
</html>
